Commercial fueling system with vapor capture

ABSTRACT

A closed fueling system with a passive vapor return comprising a cap and nozzle which selectively seal together defining passages for fuel delivery and vapor return. The cap and nozzle are sealed when the cap and nozzle are not connected together. The system optionally includes a downtube which conveys fluid to the bottom of the receiving tank, permitting filling from the bottom of the tank and minimizing atomization and vapor creation.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

BACKGROUND OF THE INVENTION

Heavy equipment, construction vehicles, aircraft, watercraft, stationaryequipment, home heating tanks and stationary bulk supply tanks aretypically refueled with their appropriate liquid fuels by a mobile fueldelivery tanker. The fuel is delivered to the receiving fuel tank usinghoses and nozzles which typically deliver fuel at a flow rate of 60-100gallons per minute. These systems typically lack vapor capture systemsand many industrial fueling applications lack a self-stopping feature.In order to manually cut off the flow of fuel when a tank is full, anoperator must stand above the fuel tank intake with a flashlight andwatch for the fuel level to reach the top of the tank. Operatorstypically receive no protection from the fuel vapor and atomized fuel. Atremendous amount of vapor and atomized fuel are generated when heavyequipment is filled because the fuel flows very fast, and because thetanks in question are very large, so the fuel may fall for one or moremeters before splashing against the bottom of the tank. Existingtechnology does not include mechanisms to decrease the amount ofsplashing. The inventor has discovered that splashing contributes toatomization and to foaming, and that vapor creation can be mitigated byminimizing the exposure of fuel to air by limiting fuel surface area.Conventional systems do not minimize the exposure of fuel to air.Because existing technology does not capture fuel vapor or atomizedfuel, vapor and atomized fuel are dispersed into the environment,covering the operator and everything else in the vicinity, includingnearby plant life. Existing fueling systems cannot easily be adapted tooperate in extreme temperatures, and therefore when they are used invery cold or very hot places the manual fuel cut off mechanismsfrequently fail when seals shrink or expand, dousing operators and thesurrounding environment with fuel.

Even aside from the obvious risk of combustion, petrochemicals such asdiesel in contact with skin are readily absorbed into the bloodstream,and contain known toxics and carcinogens such as benzene. Dieselirritates and even chemically burns skin, eyes, nose, throat, and lungs.Breathing diesel vapors can cause kidney damage and reduce the clottingability of blood, and diesel absorbed through the skin causes similarproblems. Studies have indicated that fuel exposure is associated withan increased risk of lung cancer and prostate cancer. Diesel fuel canpenetrate most glove material. Vinyl or butyl rubber gloves providelittle or no protection against diesel fuel. Spilled fuel and fuel vaporis also damaging to air and water quality, and spilled fuel contaminatesthe ground, fouls waterways and groundwater, and injures and killswildlife and surrounding plant life.

Gasoline pumps in much of the US have been equipped with fuel vaporrecovery systems at least since 1992. The systems typically include arubber sleeve that slides over the fuel nozzle and compresses againstthe external rim of the gas tank outlet which is connected to the outerchamber of a coaxial hose which leads to a containment system. Vaporthat escapes from the gas tank is pushed into the sleeve while beingvacuumed back through the coaxial hose to the containment system. Thevapor recovery system is not sealed. Any motorist knows that the rubbersleeve can be pushed back during fueling. Additionally, when the car'sgas cap has been removed, fuel vapor can escape before the nozzle andfuel vapor recovery sleeve are in place as well as after they have beenremoved. Despite these shortcomings, gas station vapor recovery systemseffectively contain around 95% of fuel vapor in these low-rate fuelingoperations, making gas stations much safer and much cleaner.

Gas station pumps dispense fuel at around 6-7 gallons per minute. In acommercial fueling situation fuel is dispensed at 60-100 gallons perminute. At these vastly higher flow rates, atomized fuel along with alarger amount of vapor are produced, and it is expelled from the tank ata rate equivalent to that of the liquid fuel flow rate, generating muchgreater pressure on any component or structure intended to contain it.It is believed that this higher pressure expulsion of vapor and atomizedfuel cannot be adequately contained by existing vapor recovery systems.

For at least this reason, a consumer gas station vapor recovery systemwill not work in a commercial context. In an unsealed situation, thepressure in a high flow context would push a conventional vapor recoverysleeve back, allowing the vapor to escape. Any vapor recovery systemusable in a sealed high flow situation must be able to withstand highpressures. Such a system should also operate in extreme weather, whereextreme temperatures changes cause dimensional change in systemcomponents. A typical unsealed system cannot operate effectively in ahigh pressure situation, and a conventional sealed system is morevulnerable to failure due to component dimensional change.

SUMMARY OF THE INVENTION

Disclosed herein is a cap for a fuel tank adapted to minimize fuelatomization during filling of said fuel tank, said fuel tank having abottom, and said cap comprising a cap structure defining a fuel carryingpassage, a valve capable of selectively sealing said passage, and adowntube in fluid communication with said fuel carrying passage andextending from said cap structure to substantially said bottom of saidfuel tank. Further disclosed herein is a fueling system adapted todeliver fuel to a receiving tank having a bottom and to remove vaporfrom said receiving tank, comprising a fuel dispensing nozzle having afirst attachment structure; a cap structure having a second attachmentstructure complementary to said first attachment structure, said capstructure being selectively affixable to an inlet of said receivingtank; and a downtube having sufficient length to convey fuelsubstantially to said bottom of said fuel receiving tank; and whereinsaid nozzle is selectively attachable to said cap structure via firstand second attachment structures, and whereby selectively attaching saidnozzle to said cap structure defines one or more fluid and vaporcommunication passages between said nozzle and said downtube, said oneor more passages capable of conveying fuel from said nozzle to saiddowntube and removing vapor from said receiving tank.

The foregoing and other objectives, features, and advantages of theinvention will be more readily understood upon consideration of thefollowing detailed description of the invention taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall perspective view of an entire system consistentwith the description herein.

FIG. 2 is cut-away perspective view of a nozzle showing separatepassages for liquid fuel and vapor return.

FIG. 3 is an enlarged side view of a one embodiment of a cap structureas disclosed and described herein.

FIG. 4 is an enlarged top view of one embodiment of a cap structuredisclosed and described herein.

FIG. 5 is an enlarged exploded view of one embodiment of a cap structuredisclosed and described herein.

FIG. 6 is enlarged perspective bottom view of one embodiment of a capstructure disclosed and described herein.

FIG. 7 is a top side view of one embodiment of a cap structure disclosedand described herein showing a downtube and siphon tube.

FIG. 8 is a side view of a receiving tank, showing a downtube, a siphontube, and fuel levels.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Disclosed herein is a fueling system that is capable of accommodatinghigh flow rates, approaches 100% vapor recovery capability, includes adrip free design leaving no wet surfaces exposed, and may include arapid internals exchange system which can accommodate a switch betweenfuel types, allow for easy maintenance, and accommodate extreme heat andcold operating conditions.

Referring now to FIG. 1, a hose structure 4 interconnects with a fuelsupply tank 2 and terminates in a specialized nozzle 6. The nozzle 6 isadapted to matingly connect with a specialized fuel tank cap structure 8mounted on the receiving fuel tank 10 of a vehicle or piece of equipmentbeing refueled. When operably connected, the nozzle 6, the fuel tank capstructure 8, the hose structure 4, and the fuel tanks at either end ofthe system 2, 10 form a substantially sealed system. The system whencorrectly operated substantially prevents leaks and/or spills of liquidfuel, fuel vapor, and atomized fuel during the refueling process. Fueland vapor can only flow when the system is operably connected andtherefore sealed. Both fuel passages and vapor passages must be aligned,operably connected, and sealed in order to permit communication ofmaterials between the hose structure and the fuel tank. If no operableconnection occurs, the respective components remain sealed, and fuel isprevented from leaving the nozzle and vapor is prevented from leavingthe receiving fuel tank.

A hose structure 4 accommodates the flow of liquid fuel from the supplytank 2 to the receiving fuel tank 10 and accommodates the flow of fuelvapor from the receiving tank 10 to the fuel supply tank 2 or to someother fuel vapor containment system. It includes one or more chamberswhich carry liquid fuel from the supply tank 2 to the receiving tank 10and one or more chambers which carry fuel vapor from the receiving tank10 to the supply tank 2. Because in a sealed system the liquid fuel mustdisplace vapor in order to fill the tank, the system should be able totransport vapor in sufficient volume so that vapor flow rate does notlimit liquid fuel flow rate, creating a balanced vapor recovery fuelingsystem. The total diameter of all vapor carrying chambers should not beless than the total diameter of all liquid fuel carrying chambers. Thechambers may be arranged in any configuration. For example, they may becoupled together in tandem, or they may be coaxial. Multiple hoses,separate or coupled together, may be used. The hose structure must bemade from a material strong enough to withstand substantial internalpressures.

As shown in FIG. 2, in order to form a seal and permit efficientconnecting and disconnecting, the fuel nozzle 6 should be adapted tomatingly interconnect with the fuel tank cap structure 8 such thatinterconnecting parts on at least one component can open or permit theopening of valves on the other component if and only if the twocomponents are appropriately connected. In this way, it is impossible todispense fuel from the nozzle 6 unless the nozzle is operably connectedto the cap structure 8 such that the fuel flows into the tank, and it isimpossible to release vapor from a receiving fuel tank 10 unless thetank 10 is operably connected to the nozzle 6 so that vapor flows intothe fuel supply truck 2 or other containment system and is not releasedinto the environment. Accidental spills from the nozzle 6 or supply fueltank 2 are far less likely. Fuel nozzle 6 may also include a manuallever 14, which opens one or more valves within the fuel nozzle 6 topermit the flow of fuel. The lever 14 may be mechanically locked unlessand until the nozzle 6 is appropriately interconnected with a fuel tankcap structure 8, making it impossible to start the flow of fuel unlessthe nozzle has a sealed connection with a receiving tank.

Referring to FIGS. 2 and 3, attachment structures permit the nozzle tobe operably sealed to the cap. Interlocking elements 18 may be locatedon the outside 20 of the fuel tank cap structure, with correspondingelements 24 located on the inside 26 of the distal end 28 of the nozzle6 such that the distal end 28 of the nozzle slides over the outside 20of the cap structure. Interlocking elements 24 may be notches oralignment grooves. The nozzle can be locked to the fuel tank capstructure in a variety of ways. For example, an annulus 30 located onthe nozzle 6 may be rotated once the nozzle is seated on the capstructure 8, creating an outside initial seal and aligning the valveswithin the nozzle 6 with the valves 42, 44 within the fuel tank capstructure 8. Only when properly positioned, the valves in bothcomponents can be opened, allowing fuel flow and vapor return confinedwithin the outside initial seal formed by the nozzle 6 and cap structure8. Should the annulus or other locking structure be unlocked, the valveswould become misaligned, and would therefore or thereby immediatelyclose.

The nozzle 6 may contain one or more manually operated valves, such as aball or butterfly valve, which may optionally be mechanically locked sothat it is rendered inoperable in its closed position absent a sealbetween the nozzle 6 and cap structure 8. Additional valves within thenozzle 6 may also be manually operated or may be automatically operatedduring the connecting process. Valves in the nozzle 6 may take anyconfiguration which maintains a sealed state until the nozzle is lockedon the cap structure 8 and/or the manual lever 14 is operated.

Valves 42, 44 in the cap structure 8 maintain a closed and sealed stateunless and until the nozzle is sealed to the cap structure, at whichpoint they may opened. The same process or step which accomplishes aseal between the nozzle 6 and the cap structure 8 may operate to openthe valves in the cap structure, or operation of the manual lever 14 onthe nozzle 6 may cause elements within the nozzle 6 to open the valvesin the cap structure. Valves 42, 44 within the cap structure 8 may bemanually opened through the operation of an additional switch or lever(not shown).

By way of example and not limitation, the valves in the cap may comprisepistons 108, 110, as shown in FIG. 5. When the nozzle 6 is engaged andforms a seal with the fuel cap housing 102, elements within the nozzle 6are aligned with the pistons 108, 110 in the cap structure 8. Thepistons may be automatically depressed by corresponding elements in thenozzle when the two components are matingly engaged. Alternatively, thepistons may be depressed by elements in the nozzle when a lever ispulled, such as the manual lever 14, which also opens a valve within thenozzle, or by another lever. When the pistons are depressed, a passageis created around each piston allowing fuel to freely flow through thecap structure 8 and into the receiving tank 10 and vapor to flow throughthe cap structure and into the hose. Fuel piston spring 112 and vaporpiston spring 114 ensure the pistons remain in a closed position unlessopened by appropriate elements within the nozzle. The springs areretained by fuel hose mount and internal spring retainers 116 and 118,which may be threaded into the fuel cap housing 102 for easy removal.

The fuel cap structure employs a fuel cap gasket 100 to assure a sealbetween the fuel cap and the fueling nozzle and prevent the escape offuel or vapor into the environment. The fuel cap gasket 100 can bemounted to the cap structure with screws or other accessible andremovable attachment structures. Fuel piston 108 carries a fuel pistongasket 104, and vapor piston 110 carries a vapor piston gasket 106.These gaskets assure that the pistons completely restrict the flow offuel and vapor when the pistons are in their closed positions. Thegaskets sit at the top of each piston, and can be compressed against theouter casing of the fuel tank cap structure when the pistons are closed.They can be quickly and easily accessed from the bottom of the capstructure by unscrewing the fuel hose mount and internal spring retainer116 and the vapor hose mount and internal spring retainer 118. Becausefuel cap gasket 100 and piston gaskets 104, 106 can be easily accessed,they can be easily inspected and replaced if worn. They can also bereplaced with materials which are appropriate for different fuel types.The same fuel cap structure can be used with different fuels simply byreplacing the gaskets with gaskets appropriate for the new fuel.

In this way, the nozzle and cap may be configured to be easily adaptedto withstand extreme temperature changes. The harshest operatingenvironments for commercial refueling systems frequently experiencebelow zero temperatures. The material used for the seals in existingsystems contracts under such circumstances, causing inadequate seals anddangerous spills. The systems disclosed herein may be designed withquick exchangeable internal components, as described above, to adapt thesystem to environmental temperature by replacing gaskets with those madeof materials rated for the appropriate temperature range. In this way,temperature change induced failures of gaskets and the spills and leaksthey cause can be prevented.

The fuel tank cap structure is affixed to the outlet of a receiving fueltank 10. When its valves are closed, the tank is sealed, and the capstructure permits no vapor or liquid fuel to escape. Referring to FIG.6, it may have an external housing 40 or other attachment structureadapted to matingly connect with a fuel nozzle 6. Within the housing 40,the cap structure defines two or more passages 41, 43, each selectivelyoccluded by valves 42, 44 which can be opened in order to permit accessto the fuel receiving tank. At least one passage 41 is dedicated todeliver liquid fuel to the receiving tank 10, and at least one passage43 is dedicated to extract fuel vapor from the receiving tank. Thepassages are situated such that when the nozzle is locked into position,the passages communicate with the appropriate lumens of the nozzlestructure such that vapor passages deliver vapor to the vapor chamber 13of the nozzle, and liquid fuel passages deliver liquid fuel from thechamber 12 of the nozzle which carries liquid fuel. The total diameterof the liquid fuel passages should equal the total diameter of the vaporpassages.

The cap structure may preferably have one or more tubes extending fromit into the fuel receiving tank. A downtube 48 extends substantiallyinto the receiving tank 10, and may extend past the bottom of the tankso that it bends and extends partially along the bottom of the tank.This tube is operably connected to the passages 41 that permit the flowof liquid fuel into the receiving tank 10, so that when the nozzle 6 isconnected to the cap structure 8 and fuel flows through the nozzle andthrough the cap structure, the fuel fills the tank by flowing throughthe downtube 48 to the bottom of the tank. For example, the downtube maybe connected to the fuel hose mount and internal spring retainer 116,shown in FIG. 5. As the fuel level 50 in the receiving tank 10 getshigher, the fuel will actually be dispersed under the existing fuellevel preventing the fuel from falling through the air in the tank. Thedowntube 48 allows the tank to fill from the bottom up, and prevents thefuel from splashing, which significantly reduces the foaming of thefuel, which in turn eliminates the creation of atomized fuel from fueldisturbance to be disbursed in the air. It also substantially decreasesthe formation of fuel vapor by minimizing the surface area where liquidfuel is exposed to air.

One or more siphon tubes 52 extend into the tank to a pre-determinedfill level, indicated by dashed line 51 in FIG. 8. The siphon tube ortubes 52 are operably connected to the vapor return passages 43, suchthat vapor return structures in the nozzle and vapor return structuresof the hose can remove fuel vapor from the tank even without pumpingassistance. The liquid fuel is pumped from the fuel supply tank 2 intothe fuel carrying lumen of the hose structure 4, through the nozzle 6and the cap structure 8, and into the receiving tank 10 at significantvelocity. The flow of fuel into the receiving tank displaces fuel vapor,and in a sealed system expels the vapor at significant positivepressure. The removal of fuel from the fuel supply tank also generates anatural negative pressure vacuum in the vapor return portion of thesealed system, which is capable of extracting vapor from the tankwithout additional pumping. This combination of negative and positivepressure working together to replace liquid mass with gas is known as abalanced vapor return system.

The hose structure 4, nozzle 6, and fuel tank cap structure 8 must becapable of withstanding the significant pressures generated by the highrate of the fuel flow. The connection of the nozzle to the cap structurealso must be capable of withstanding high pressure. For that reason, thepressure-based connections used in consumer grade gas stations will notwork. An interlock or something equivalent to an interlock is necessary.

When the fuel level 50 in the tank covers the bottom of the siphon tubeor tubes 52, it causes a change in pressure within the vapor returnsection of the nozzle, which in turn causes suction across a diaphragmthat can disengage the manual lever, causing all valves to shut, cuttingoff the flow of fuel and sealing both the nozzle and fuel tank capstructure. It is then safe for the operator to unlock and/or remove thenozzle from the cap structure. Separating the nozzle from the cap andthe mating surfaces of the plungers leaves no wet surfaces exposed.Spills of liquid fuel and release of vapor are far less likely than withconventional systems.

The fuel tank cap structure can be a universal structure pared with aninstall kit specific to the existing fuel fill spouts of commonly usedfuel receiving tanks so that the cap structure may be affixed to anexisting fuel tank inlet without significant modification. The fuel capstructure seals the fuel tank. A two way check valve may be installed onan existing vent to regulate pressure differences inside the receivingtank due to temperature changes which may cause contraction andexpansion of fuel.

The terms and expressions which have been used in this specification areintended to describe the invention, not limit it. The scope of theinvention is defined and limited only by the following claims.

What is claimed is:
 1. A cap for a fuel tank adapted to minimize fuelatomization during filling of said fuel tank, said fuel tank having abottom, and said cap comprising: a) a cap structure defining a fuelcarrying passage; b) a valve capable of selectively sealing saidpassage; and c) a downtube in fluid communication with said fuelcarrying passage and extending from said cap structure to substantiallysaid bottom of said fuel tank.
 2. The cap of said claim 1 wherein saidcap structure further defines one or more vapor carrying passagesadapted to allow fuel vapor to leave a fuel receiving tank duringfueling.
 3. The cap of claim 1 wherein said valve is a piston valve. 4.The cap of claim 1, further comprising a member removably affixed tosaid cap structure, wherein said valve is mounted on said member.
 5. Thecap structure of claim 4 wherein said member is threaded.
 6. The cap ofclaim 4, further comprising a gasket associated with said valve, saidgasket being accessible via the removal of said member from said capstructure.
 7. The cap of claim 1 wherein said cap structure defines anannular member adapted to interlock with a fuel dispensing nozzle. 8.The cap of claim 1 wherein said valve is adapted to be selectivelyoperated upon the engagement of a fuel dispensing nozzle with saidvalve.
 9. The cap of claim 2 wherein each said one or more vaporcarrying passages is associated with a siphon tube.
 10. A fueling systemadapted to deliver fuel to a receiving tank having a bottom and toremove vapor from said receiving tank, comprising: a) a fuel dispensingnozzle having a first attachment structure; b) a cap structure having asecond attachment structure complementary to said first attachmentstructure, said cap structure being affixable to an inlet of saidreceiving tank; and c) a downtube having sufficient length to conveyfuel substantially to said bottom of said fuel receiving tank; and d)wherein said nozzle is selectively attachable to said cap structure viafirst and second attachment structures, and e) whereby selectivelyattaching said nozzle to said cap structure defines two or more fluidand vapor communication passages between said nozzle and said downtube,said two or more passages capable of conveying fuel from said nozzle tosaid downtube and removing vapor from said receiving tank.
 11. Thesystem of claim 10 wherein said cap structure is sealed when said nozzleis not attached to said cap structure.
 12. The system of claim 10wherein said nozzle is sealed when said nozzle is not attached to saidcap structure.
 13. The system of claim 10 wherein each said passage isassociated with at least one valve.
 14. The system of claim 13 whereinat least one said valve is a piston valve.
 15. The system of claim 11,further comprising a member removably affixed to said cap structure andwherein said valve is mounted on said member.
 16. The system of claim 13wherein said member is threaded.
 17. The system of claim 13 furthercomprising a gasket associated with said valve and wherein said gasketcan be selectively accessed by removing said member from said capstructure.
 18. The system of claim 10 wherein said cap structurecomprises an annular member adapted to interlock with said fueldispensing nozzle.
 19. The cap of claim 10 wherein said valve is adaptedto be operated by said fuel dispensing nozzle.
 20. The cap of claim 10wherein each said one or more vapor carrying passages is associated witha siphon tube.